Metal etching mordant



or Tech. To the Patented May 11, 1937 UNITED STATES PATENT OFFIQE NoDrawing.

Application December 10, 1936,

Serial No. 115,264

4 Claims.

This invention relates to an etching or cutting mordant or solution formetal, practically all of the common metals, and particularly forcopper, bronze, brass, aluminum, and such special metals as Monel,pewter and nickel-silver.

It is aimed to provide an etching mordant superior to those in use inthat it will etch more rapidly and without emission of an objectionableodor. I have found that the mordant will etch straight through withoutundercutting and that it cuts entirely through metal up to oz. quicklyand smoothly. As is well known, the emission of fumes by existingmordants is injurious to health.

It is further aimed to provide a mordant which will not injure the barehands and which is of more general adaptation in that it will etch morethan one or two metals.

In carrying out the invention, 2 oz. of potassium dicrornate, eitherpowdered or crystal, is dissolved in 16 oz. of water. To such solutionof potassium dichromate, I add 1 oz. of hydrochloric acid, 1 oz. ofnitric acid and oz. of sulphuric acid. All of the chemicals mentionedare C. 1?.

mixture potassium bichromate and the various acids mentioned, I add oz.of

(Cl. IL-42) liquid castile soap. Such liquid castile soap is of thestrength of 1 oz. of soap dissolved in 8 oz. of water.

The mordant or solution thus prepared possesses all of the advantagespreviously mentioned.

I might add that the resist used in connection with the mordant orsolution is an asphaltum or a wax resist.

Various changes may be made within the spirit and scope of theinvention.

I claim as my invention:-

1. A metal etching mordant having therein potassium dichromate,hydrochloric acid, nitric acid, sulphuric acid and soap.

2. A metal etching mordant having therein potassium dichrornate,hydrochloric acid, nitric acid, sulphuric acid and castile soap.

3. A metal etching mordant having therein potassium dichromate,hydrochloric acid, nitric acid, sulphuric acid and liquid castile soap.

4. A metal etching mordant having therein a water solution containing 2oz. of potassium dichromate, 1 oz. of hydrochloric acid, 1 oz. of nitricacid, /2 oz. of sulphuric acid an 1 /2 oz. of liquid castile soap.

EDWARD S. TRUI'I'I.

